Ground lift- possible adverse consequences
The summary of transmission line properties indicates disconnecting the outer conductor of a coaxial cable (ground lift) will force the return current to flow in some other conductor that is much further away. This will enlarge the ratio b/a of outer to inner conductor radius and so increase the characteristic impedance of the cable. If the cable was originally properly terminated, it will no longer be so. Ground lift of a coaxial cable will cause signal distortion because the various frequency components that constitute a signal will propagate in substantially different manners.